We implemented a heat stress reduction system for our dairy sheep farm in 2024. With the assistance from a NEDBIC Dairy Farm Improvement & Modernization grant, we purchased and installed shade and ventilation equipment for our flock. This heat stress reduction equipment reduced the stress on the animals and increased the efficiency of our labor and water management. The heat stress reduction program was inspired by Alberto Atzori’s presentation on Heat Stress at the DSANA 2023 Virtual Symposium.
Background
During the summer, our milking flock lives on pastures which offer little shade. We rotate their grazes twice a day after milking. In 2022 there were 112 days where the heat index was over 75°, 85 days over 80° and 63 days over 84°. In 2023 the number of days were 92, 76 and 54 respectively. In 2024 the number of days were 109, 86 and 60 respectively.
In the past, when the heat index was over 80°, we would move the sheep into our barn mid-morning to avoid the heat of the day. We have a small bank barn with two ventilation fans. This procedure kept the sun off the sheep but did not reduce the temperature much because the ceiling of the barn is low and there is only one window and the main barn doors that we open to provide ventilation. Additionally, it takes about an hour to muck the barn after we put the sheep into the barn each day.
The Project
With the Grant Project, we purchased three pieces of equipment:
- A mobile shade unit: SH600 from Shade Haven, a 30’ diameter round unit on wheels.
- A semi-permanent shade unit: Rush-Co 31’ square unit.
- A ventilation fan and custom-built shade structure for the holding area prior to milking.
The Shade Haven mobile shade structure for the rotational grazes is our favorite unit. Our grazes rotate on 14-acres of pasture that offer little shade for 44 dairy ewes during the summer months. The Shade Haven structure is a 30’ round umbrella on wheels. The unit includes a salt lick and mineral tray and the water trough is connected to it. When we move the graze, we hook the Shade Haven unit up to our four-wheeler vehicle and tow it to the next graze. The water, salt and minerals all move with the shade unit. The unit also provides shade for the water trough.
The Shade Haven mobile shade unit is easy to furl and unfurl when a hurricane approaches. There are no tools or ladders needed, just a three-foot stick with a hook on the end. It is stable and strong and we only furled the unit once during the summer of 2024.
The second shade structure we implemented was the Rush-Co semi-permanent 31’ square unit. This unit is erected in the paddock where the lambs and yearlings spend their days during the summer. These animals graze in the evenings on a different pasture. Their daytime paddock shade unit provides shade for 40 lambs and 30 yearlings during the summer. It also provides shade for their water trough decreasing the water temperature.
This Rush-co unit is very effective at providing shade, although it was difficult to assemble. It took two people four days to assemble it. Additionally, to assemble it, we had to rent a lift because the unit is 14’ high. To avoid renting a lift twice a year to winterize the unit (furl and unfurl the cover), we will invest in a platform for our tractor. In retrospect, I should have requested that the manufacturer shorten the legs by two feet so it would be easier to assemble and winterize. We may shorten the legs this winter to facilitate furling and unfurling the unit’s cover in the future.
The third shade structure included in the Grant was the construction of a ventilated shade structure over the holding area adjacent to the milking parlor where the sheep wait to be milked. This structure has a temporary shade roof that can be rolled up for winterization. It also includes a fan to increase ventilation. We milk twice a day at 5am and 5pm and this structure provides shade and ventilation during the afternoon milking.
Results
During the summer of 2024, after installing the shade units, we did not move the sheep into the barn at all. This saved labor since we did not need to muck out the barn. During the prior year, 2023, we moved the sheep into the barn 43 days to avoid summer heat. This saves about 1.5 hours of labor each day we did not have to move the sheep to the barn.
Our average milk production per ewe increased by 5% in 2024 over 2023. This increase is partly caused by improved genetics. The temperatures of 2024 were hotter than 2023 (60 days over 84° in 2024 vs 54 days in 2023) which may have offset the positive impact on milk production from the new shade structures.
In 2024 we did not treat any ewes with intra-mammary antibiotics for mastitis although we dried of four teats on four ewes during the year. During the prior year we treated ewes 55 times for mastitis. This decrease in treatments may be related to reduced heat stress from the shade units.
Overall, the labor savings, the shade provided for the water and the sheep while on pasture was a big win.
